Sand separator for petroleum and natural gas wells

Abstract

A sand separator for capturing sand and rock debris from recovered natural gas fracturing fluid includes a cylindrical, high-pressure-rated vessel disposed vertically and immediately downstream of the gas wellhead. High pressure fracturing fluid enters the top of the separator into an inner flue extending coaxially downward to terminate a spaced distance above the bottom of the vessel. Transverse baffles spaced apart along the length of the flue extend through the flue to the inner walls of the vessel to keep the flue centered within the separator. As the fluid enters the separator, openings through the flue near the vessel inlet permit lighter weight and gaseous constituents to escape the fluid and bypass the flue, thereby reducing the velocity of the fluid remaining inside the flue. As the remaining fluid falls to the bottom of the vessel, it further slows as it reverses direction to rise between the flue and the vessel walls. At the bottom of the vessel, sand and rock debris precipitates out of the slowed fluid and accumulates above a clean-out valve by which the debris periodically may be removed. The gas and fluid recombine relatively free of sand and rock debris and exit the vessel at one or more outlet ports through the vessel walls. The sand separator functions in both exploration and production wells for both petroleum and natural gas.

We claim: 
     
       1. A sand separator for hydrocarbon fluids comprising
 a cylindrical vessel having
 vessel walls concentric about a longitudinal vessel axis and defining a vessel interior surrounded by a vessel exterior, 
 a vessel fluid inlet disposed at a vessel upper end and communicating between the vessel interior and the vessel exterior; 
 a sand discharge outlet disposed at a vessel lower end opposite the fluid inlet; 
 a vessel fluid outlet disposed within the vessel walls a spaced distance below the fluid inlet; and 
 a settling chamber disposed above the sand discharge outlet; 
 
 a flue descending a spaced distance within the vessel parallel to the vessel axis, the flue having
 a flue inlet coupled to the vessel fluid inlet; 
 a flue outlet disposed above the settling chamber and the sand discharge outlet; 
 flue walls extending between the flue inlet and flue outlet and surrounding a flue interior and defining an upper vessel chamber outside the flue interior, and 
 a plurality of gas ports disposed through the flue walls adjacent the fluid inlet and communicating between the flue interior with the upper vessel chamber; and 
 
 fluid directing means coupled to and in fluid communication with the vessel inlet for directing hydrocarbon fluid from the fluid inlet into the flue. 
 
     
     
       2. The sand separator of  claim 1  wherein the fluid directing means comprises
 nozzle means coupled to the vessel fluid inlet and extending substantially parallel to the vessel axis for directing hydrocarbon fluids from the fluid inlet into flue. 
 
     
     
       3. The sand separator of  claim 1  wherein the fluid directing means comprises
 a downcomer nozzle coupled to the vessel fluid inlet and extending downward a spaced distance within the flue 
 
       whereby the hydrocarbon fluids are discharged within the flue below the plurality of gas ports. 
     
     
       4. The sand separator of  claim 1  and further comprising
 fluid buffering means disposed across the flue interior for buffering and slowing flow of hydrocarbon fluids within the flue. 
 
     
     
       5. The sand separator of  claim 4  wherein the fluid buffering means comprises
 at least one flue baffle coupled to the flue walls, the at least one flue baffle
 extending radially outward from the flue walls to engage the vessel walls to affix the flue relative to the vessel axis and the vessel walls; and 
 extending diametrically within the flue interior transverse the flue interior whereby the at least one flue baffle partially slows hydrocarbon fluid flow within the flue interior. 
 
 
     
     
       6. The sand separator of  claim 1  and further comprising
 rack means disposed on the vessel exterior for supporting the sand separator in a substantially vertical orientation during operation thereof. 
 
     
     
       7. The sand separator of  claim 6  wherein the rack means comprises
 a platform disposed a spaced distance beneath the sand discharge outlet, the platform having
 a base adapted to rest on a surface; 
 a catwalk disposed on the base; and 
 a plurality of platform struts extending from the base to the vessel exterior; 
 
 an upright skid coupled to one side of the base and extending vertically upward parallel the vessel, the skid having a plurality of skid braces extending to the vessel exterior. 
 
     
     
       8. The sand separator of  claim 7  and further comprising
 a plurality of wheels disposed on the skid at its end adjacent the vessel fluid inlet. 
 
     
     
       9. The sand separator of  claim 7  and further comprising
 a plurality of lifting lugs disposed on the vessel exterior opposite the skid. 
 
     
     
       10. A separator for segregating solid and liquid constituents in a fluid stream, the separator comprising
 a cylindrical vessel having
 vessel walls surrounding and defining a vessel interior having a longitudinal vessel axis extending between upper and lower vessel ends; 
 a fluid inlet disposed at the upper vessel end; 
 a sand discharge outlet disposed at the lower vessel end opposite the fluid inlet; and 
 a fluid outlet disposed along the vessel walls a spaced distance below the vessel fluid inlet; 
 
 a cylindrical flue descending a spaced distance within the vessel coaxial with the vessel axis, the flue having
 a flue inlet coupled to the vessel fluid inlet; 
 a flue outlet disposed above the settling chamber and the sand discharge outlet; 
 flue walls extending between the flue inlet and flue outlet and surrounding a flue interior and defining an upper vessel chamber concentric the flue interior, and 
 a plurality of gas ports disposed through the flue walls adjacent the fluid inlet and communicating between the flue interior with the upper vessel chamber; and 
 
 a downcomer nozzle coupled to the vessel fluid inlet and extending coaxially downward a spaced distance within the flue 
 
       whereby the hydrocarbon fluids are discharged within the flue below the plurality of gas ports. 
     
     
       11. The separator of  claim 10  and further comprising
 at least one flue baffle coupled to the flue walls, the at least one flue baffle
 extending radially outward from the flue walls to engage the vessel walls to affix the flue relative to the vessel axis and the vessel walls; and 
 extending diametrically within the flue interior transverse the flue interior whereby the at least one flue baffle partially slows hydrocarbon fluid flow within the flue interior. 
 
 
     
     
       12. The separator  claim 10  and further comprising
 a platform disposed a spaced distance beneath the sand discharge outlet, the platform having
 a substantially rectangular base adapted to rest on a substantially horizontal surface; 
 a catwalk disposed on the base; and 
 a plurality of platform struts extending from at least two corners of the base to the vessel exterior; 
 
 an upright skid coupled to one side of the platform base and extending vertically upward parallel the vessel a spaced distance above the vessel inlet, the skid having
 a plurality of skid braces extending to the vessel exterior; and 
 a plurality of wheels disposed on the skid at its end adjacent the vessel fluid inlet; and 
 
 a plurality of lifting lugs disposed on the vessel exterior opposite the skid. 
 
     
     
       13. An improved method of separating sand and solid debris from a hydrocarbon fluid, the method comprising
 providing a sand separator having cylindrical walls surrounding a vertical axis and defining a separator interior, the separator further having
 a fluid inlet disposed at an upper end of the separator; 
 a sand discharge outlet disposed at a lower end of the separator; 
 a fluid outlet disposed between the upper and lower ends of the separator; 
 a coaxial flue coupled to the fluid inlet interior and extending coaxially downward to a flue outlet disposed above a settling chamber atop the sand discharge outlet; 
 gas ports communicating between separator interior and a flue interior; and 
 a downcomer nozzle extending from the fluid inlet into the flue interior past the gas ports; then 
 
 coupling the fluid inlet to a well head; 
 coupling the fluid outlet to a fluid storage means; and 
 coupling the sand discharge outlet to a sand disposal means; then 
 operating the sand separator to
 direct hydrocarbon fluid from the well head into the separator interior through the fluid inlet; 
 channel the hydrocarbon fluid to flow axially downward through the flue interior to the settling chamber; 
 allow dissolved gas in the hydrocarbon fluid to escape through the gas ports into the separator interior, thereby slowing the hydrocarbon fluid flow; 
 allow sand and other solid debris suspended within the hydrocarbon fluid to precipitate out of the slowed hydrocarbon fluid within the settling chamber; 
 direct the remaining hydrocarbon fluid upward within the separator between the flue and the separator walls out the fluid outlet to the fluid storage means; and 
 periodically open the sand discharge outlet to discharge said sand and other solid debris accumulated within the settling chamber. 
 
 
     
     
       14. The improved method of  claim 13  and including the additional steps of
 providing at least one baffle coupled to the flue, the at least one baffle
 extending radially outward from the flue to engage the separator walls to affix the flue relative to the vertical axis and the separator walls; and 
 extending diametrically across the flue interior whereby the at least one flue baffle further slows hydrocarbon fluid flow within the flue interior. 
 
 
     
     
       15. The improved method of  claim 13  and including the additional step of
 providing a platform disposed beneath the sand discharge outlet and having
 a substantially rectangular base adapted to rest on a substantially horizontal surface; 
 a catwalk disposed on the base; and 
 a plurality of platform struts extending from at least two corners of the base to the separator; 
 
 an upright skid coupled to one side of the platform base and extending vertically upward parallel the vertical axis a spaced distance above the fluid inlet, the skid having
 a plurality of braces extending to the separator; and 
 a plurality of wheels disposed on the skid opposite the platform; and 
 
 a plurality of lifting lugs disposed on the separator opposite the skid. 
 
     
     
       16. A sand separator for hydrocarbon fluids comprising
 a cylindrical vessel having
 vessel walls concentric about a longitudinal vessel axis and defining a vessel interior surrounded by a vessel exterior, 
 a vessel fluid inlet disposed at a vessel upper end and communicating between the vessel interior and the vessel exterior; 
 a sand discharge outlet disposed at a vessel lower end opposite the fluid inlet; and 
 a vessel fluid outlet disposed within the vessel walls a spaced distance below the fluid inlet; 
 
 fluid channeling means depending from the vessel upper end for channeling fluid from the fluid inlet into a settling chamber disposed above the sand discharge outlet; 
 fluid directing means coupled to and in fluid communication with the vessel inlet for directing hydrocarbon fluid from the fluid inlet into the fluid channeling means; 
 a platform disposed a spaced distance beneath the sand discharge outlet, the platform having
 a platform base; 
 a catwalk disposed on the platform base; and 
 a plurality of platform struts extending from the platform base to the vessel exterior; and 
 
 an upright skid coupled to the platform base and extending parallel the vessel, the skid having a plurality of skid braces extending to the vessel exterior. 
 
     
     
       17. The sand separator of  claim 16  wherein the fluid channeling means comprises
 a flue coupled to the vessel fluid inlet, the flue having
 flue walls defining a flue interior and an upper vessel chamber outside the flue within the vessel; and 
 a plurality of gas ports disposed within the flue walls adjacent the vessel inlet and communicating between the flue interior with the upper vessel chamber. 
 
 
     
     
       18. The sand separator of  claim 17  wherein the fluid directing means comprises
 a nozzle coupled to the vessel fluid inlet and extending into the flue past the gas ports.